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Reversibility in radionuclide/bentonite bulk and colloidal ternary systems

Published online by Cambridge University Press:  02 January 2018

Nick Sherriff ,
Ragiab Issa ,
Katherine Morris ,
Francis Livens ,
Sarah Heath  and
Nick Bryan
Nick Sherriff
Affiliation:
Centre for Radiochemistry Research, School of Chemistry, University of Manchester, Manchester M13 9PL, UK
Ragiab Issa
Affiliation:
Centre for Radiochemistry Research, School of Chemistry, University of Manchester, Manchester M13 9PL, UK
Katherine Morris
Affiliation:
Research Centre for Radwaste and Decommissioning, School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester M13 9PL, UK
Francis Livens
Affiliation:
Centre for Radiochemistry Research, School of Chemistry, University of Manchester, Manchester M13 9PL, UK Research Centre for Radwaste and Decommissioning, School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester M13 9PL, UK
Sarah Heath
Affiliation:
Centre for Radiochemistry Research, School of Chemistry, University of Manchester, Manchester M13 9PL, UK
Nick Bryan*
Affiliation:
National Nuclear Laboratory, 5th Floor, Chadwick House, Birchwood, Warrington WA3 6AE, UK
*
*E-mail: [email protected]
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Abstract

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Ternary systems of 152Eu(III), bulk bentonite and ethylenediaminetetraacetic acid (EDTA) ([Eu] = 7.9 × 10–10 M; pH = 6.0–7.0) have been studied. Without EDTA, there was slow uptake in a two-stage process, with initial rapid sorption of Eu(III) (96%), followed by slower uptake of a much smaller fraction (3.0% over a period of one month). The reversibility of Eu(III) binding was tested by allowing Eu(III) to sorb to bentonite for 1–322 days. EDTA was added to the pre-equilibrated Eu bentonite systems at 0.01 M, a concentration that was sufficient to suppress sorption in a system where EDTA was present prior to the contact of Eu(III) with bentonite. A fraction of the Eu was released instantaneously (30–50%), but a significant amount remained bound. With time, the amount of Eu(III) retained by the bentonite reduced, with a slow fraction dissociation rate constant of approximately 4.3 × 10–8 s–1 (values in the range 2.2 × 10–8 – 1.0 × 10–7 s–1) for pre-equilibration times ≥7 days. Eventually, the amount of Eu(III) remaining bound to the bentonite was within error of that when EDTA was present prior to contact (4.5% ± 0.6), although in systems with pre-equilibration times >100 days, full release took up to 500 days. Europium interactions with colloidal bentonite were also studied, and the dissociation rate constant measured by a resin competition method. For the colloids, more Eu was found in the slowly dissociating fraction (60–70%), but the first-order dissociation rate constant was faster, with an average rate constant of 8.8 × 10–7 s–1 and a range of 7.7 × 10–7 –9.5 × 10–7 s–1. For both bulk and colloidal bentonite, although slow dissociation was observed for Eu(III), there was no convincing evidence for 'irreversible' binding.

Keywords

ternary systemsbentoniteethylenediaminetetraacetic acidEDTAeuropium152Eu(III)reversibilitydissociation rate constant
Type
Research Article
Information
Mineralogical Magazine , Volume 79 , Issue 6 , November 2015 , pp. 1307 - 1315
Creative Commons
Creative Common License - CCCreative Common License - BY
Copyright © The Mineralogical Society of Great Britain and Ireland 2015. This is an open access article, distributed under the terms of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2015

References

Bouby, M., Geckeis, H., Lutzenkirchen, J., Mihai, S. and Schafer, T. (2011) Interaction of bentonite colloids with Cs, Eu, Th and U in presence of humic acid: A flow field-flow fractionation study. Geochimica et Cosmochimica Acta, 75, 3866–3880.CrossRefGoogle Scholar
Bryan, N.D., Jones, D.L.M., Keepax, R.E., Farrelly, D.H., Abrahamsen, L.G., Warwick, P. and Evans, N. (2007) The role of humic non-exchangeable binding in the promotion of metal ion transport in the environment. Journal of Environmental Monitoring, 9, 329–347.CrossRefGoogle ScholarPubMed
Comans, R.N.J. (1987) Adsorption, desorption and isotopic exchange of cadmium on illite: evidence for complete reversibility. Water Research, 21, 1573–1576.CrossRefGoogle Scholar
Comans, R.N.J., Haller, M. and Depreter, P. (1991) Sorption of cesium on illite—nonequilibrium behavior and reversibility. Geochimica Cosmochimica Acta, 55, 433–40.CrossRefGoogle Scholar
de Koning, A. and Comans, R.N.J. (2004) Reversibility of radiocaesium sorption on illite. Geochimica et Cosmochimica Acta, 68, 2815–2823.CrossRefGoogle Scholar
Geckeis, H., Schäfer, T., Hauser, W., Rabung, T., Missana, T., Degueldre, C, Mori, A., Eikenberg, J., Fierz, T. and Alexander, W.R. (2004) Results of the colloid and radionuclide retention experiment (CRR) at the Grimsel test site (GTS), Switzerland — impact of reaction kinetics and speciation on radionuclide migration. Radiochimica Acta, 92, 765–774.CrossRefGoogle Scholar
Huber, F., Kunze, P., Geckeis, H. and Schäfer, T (2011) Sorption reversibility kinetics in the ternary system radionuclide—bentonite colloids/nanoparticles — granite fracture filling material. Applied Geochemistry, 26, 2226–2237.CrossRefGoogle Scholar
Ivanov, P., Griffiths, T., Bryan, N.D., Bozhikov, G. and Dmitriev, S. (2012) The effect of humic acid on uranyl sorption onto bentonite at trace uranium levels. Journal of Environmental Monitoring, 14, 2968–2975.CrossRefGoogle ScholarPubMed
Missana, T., Alonso, Ú., García-Gutiérrez, M. and Mingarro, M. (2008) Role of bentonite colloids on europium and plutonium migration in a granite fracture. Applied Geochemistry, 23, 1484–1497.CrossRefGoogle Scholar
Monsallier, J.M., Schuessler, W., Buckau, G., Rabung, T., Kim, J.I., Jones, D., Keepax, R. and Bryan, N. (2003) Kinetic Investigation of Eu(III)-Humate Interactions by Ion Exchange Resins. Analytical Chemistry, 75, 3168–3174.CrossRefGoogle ScholarPubMed
Möri, A., Alexander, W.R., Geckeis, H., Hauser, W., Schäfer, T., Eikenberg, J., Fierz, T., Degueldre, C. and Missana, T (2003) The colloid and radionuclide retardation experiment at the Grimsel Test Site: influence of bentonite colloids on radionuclide migration in a fractured rock. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 217, 33–47.CrossRefGoogle Scholar
Nash, K.L., Brigham, D., Shehee, T.C. and Martin, A. (2012) The kinetics of lanthanide complexation by EDTA and DTPA in lactate media. Dalton Transactions, 41, 14547–14556.CrossRefGoogle ScholarPubMed
Pitois, A., Ivanov, P.I., Abrahamsen, L.G., Bryan, N.D., Taylor, R.J. and Sims, H.E. (2008) Magnesium hydroxide bulk and colloid-associated 152Eu in an alkaline environment: Colloid characterization and sorption properties in the presence and absence of carbonate. Journal of Environmental Monitoring, 10, 315–24.CrossRefGoogle Scholar
Schäfer, T., Geckeis, H., Bouby, M. and Fanghänel, T. (2004) U, Th, Eu and colloid mobility in a granite fracture under near-natural flow conditions. Radiochimica Acta, 92, 731–737.CrossRefGoogle Scholar
Wold, S. (2010) Sorption of prioritized elements on montmorillonite colloids and their potential to transport radionuclides. SKB Technical Report, TR-10-20. SKB, Stockholm.Google Scholar